A method that improves the game playability (i.e., adds interest to the game) by exchanging game data between game devices has been known. For example, Japanese Patent No. 4073885 discloses technology that enables automatic game data exchange by allowing the players to provide exchange target game data in advance. JP-A-2010-88694 discloses technology that allows a player who desires to play the game with another player to select a multi-player mode in advance, transmits a multi-player play request in the selected mode to another player who plays the same game via a game server, and implements multi-player play in the selected mode when the other player has agreed to participate in multi-player play.
An item that can be used by a character or a player character used for multi-player play has been normally exchanged between game devices as the game data.